# Itraconazole for Dogs: Dosage Itraconazole for dogs dosage is not a one-size-fits-all number. Most veterinarians start around 5 mg/kg once daily for fungal infections, then adjust based on how your dog responds and, for serious infections, on blood drug levels [1]. An itraconazole for dogs dosage chart can help you understand the ranges, but only your veterinarian can set the actual dose for your dog. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - Itraconazole is a prescription antifungal used for ringworm (dermatophytosis) and deep fungal infections such as blastomycosis. - A common starting dose for blastomycosis in dogs is 5 mg/kg once daily, but most dogs need at least one adjustment after therapeutic drug monitoring [1]. - Dose and duration depend on the infection, your dog's weight, liver values, and other medications. - Give it with food to improve absorption, and never split, crush, or compound it without your veterinarian's instructions. - If you miss a dose, call your veterinarian for guidance instead of doubling up on your own. ## What Itraconazole Is and What Veterinarians Use It For Itraconazole is an oral triazole antifungal. Veterinarians prescribe it for two broad categories of fungal disease in dogs. The first is superficial skin infection, usually ringworm. Ringworm is caused by dermatophyte fungi that live in hair follicles and the outer skin layer. Itraconazole is one of the standard treatments, and many dogs clear the infection with a course lasting several weeks. The second category is systemic mycosis, meaning fungal infection inside the body. Blastomycosis is the best-studied example in dogs. It usually starts in the lungs and can spread to the eyes, skin, bones, and nervous system. Itraconazole is a widely used treatment for blastomycosis, but serum drug concentrations vary widely between individual dogs [1]. That variability is why monitoring matters so much for these cases. Less commonly, veterinarians use itraconazole for other deep fungal infections. The exact plan depends on which fungus is involved and how sick your dog is. ## How Itraconazole Works Itraconazole blocks a step in the fungal cell membrane production line. Specifically, it interferes with an enzyme the fungus needs to make ergosterol, a key building block of its cell membrane. Without enough ergosterol, the fungal cell membrane weakens and the fungus stops growing normally. This is why itraconazole is called a fungistatic drug in many situations. It does not always kill the fungus outright. It holds it in check while your dog's immune system clears the infection. That has two practical consequences for owners. First, treatment takes weeks to months, not days. Second, your dog's immune system has to do part of the work, so dogs with weakened immunity may need longer courses or different plans. Itraconazole also interacts with many other drugs because it affects liver enzymes that process medications. That interaction risk is one reason your veterinarian needs a full list of everything your dog takes. ## Itraconazole for Dogs Dosage Chart by Weight: What the Numbers Mean Here is the honest answer about an itraconazole for dogs dosage chart by weight. There is no universal published chart that covers every situation, because the right dose depends on the infection being treated and on individual drug absorption. What exists is a starting range that veterinarians use, followed by adjustment. For blastomycosis, a prospective study in dogs started treatment at 5 mg/kg per day and then adjusted doses to keep trough serum concentrations within a target range of 2 to 7 μg/mL [1]. Twelve of 14 dogs needed at least one dose adjustment, and 9 dogs needed more adjustments even after they first reached the target range [1]. That tells you something important. The starting dose is a starting point, not a final answer. A separate study of 97 samples from 14 dogs with blastomycosis found no significant association between the itraconazole dose given and the resulting serum concentration [2]. In other words, two dogs of the same weight on the same mg/kg dose can end up with very different drug levels in their blood. Body weight alone does not predict absorption. ### Why a Simple Weight Chart Is Not Enough Weight-based dosing is still how veterinarians start. It is the practical first step. But several factors shift the picture after that. - Liver function affects how fast the drug is cleared. - Stomach contents affect absorption. Food increases itraconazole absorption substantially. - Individual variation in absorption is large, as the monitoring studies show [2][1]. - Other medications can raise or lower itraconazole levels. - The target fungus matters. Ringworm and blastomycosis are not treated identically. If you have seen an itraconazole for dogs dosage chart by weight pdf online, treat it as background reading only. Do not use it to dose your dog at home. ### How the Dose Is Actually Set Your veterinarian calculates the dose from your dog's weight and health status. For serious systemic infections, they may also recommend therapeutic drug monitoring. That means collecting a blood sample, usually a trough level taken before the next dose, and measuring how much drug is actually in your dog's bloodstream [1]. The target range used in the blastomycosis study was 2 to 7 μg/mL [1]. If your dog's level is below that, the dose may go up. If it is above, the dose may come down. Interestingly, dose changes in that study often alternated, with an increase at one visit followed by a decrease at the next, or the reverse [1]. This is normal. It reflects how carefully veterinarians fine-tune treatment. One more technical point. The lab method used to measure itraconazole matters. A culture-based bioassay and liquid chromatography-mass spectrometry do not give equivalent results, and the choice of assay can influence dosage adjustment decisions [2]. If your dog's levels are being monitored, your veterinarian is interpreting results with the specific assay in mind. ### How Itraconazole Is Given Give itraconazole with food unless your veterinarian says otherwise. Food improves absorption, and better absorption means more consistent drug levels. Capsules should be swallowed whole in most cases. If your dog is small or a pill is hard to give, ask your veterinarian before you open, split, or crush anything. Compounded liquid forms exist, but the formulation and concentration vary, so follow the label exactly. Do not switch between brands or formulations on your own. A different product can change how much drug your dog actually absorbs. ### What to Do About a Missed Dose If you miss a dose, do not double the next one. Call your veterinarian or your pet's pharmacy for instructions. In many cases the guidance is to give the missed dose when you remember if it is still close to the scheduled time, or to skip it and resume the normal schedule if it is almost time for the next dose. Your veterinarian will tell you which applies to your dog. Consistency matters with antifungals. Set a phone reminder and pair the dose with a meal so it becomes part of the daily routine. ## Common and Serious Side Effects Most dogs tolerate itraconazole, but side effects happen. The table below covers what owners most often see. | Side effect | How common or serious | What to do | |---|---|---| | Vomiting, nausea, or reduced appetite | Common, usually mild | Give with a full meal. Call your veterinarian if it persists more than a day or two. | | Diarrhea | Common, usually mild | Offer bland food if your veterinarian approves. Report bloody or severe diarrhea right away. | | Lethargy | Can be mild or a sign of drug levels that are too high | Call your veterinarian if your dog seems unusually tired or weak. | | Liver enzyme elevation | Uncommon but serious | Veterinarians monitor liver values with blood work during treatment. Keep monitoring appointments. | | Jaundice (yellow gums, eyes, or skin) | Rare but serious | Stop and seek veterinary care the same day. | | Skin sores or swelling on the legs | Uncommon, associated with higher doses in some dogs | Report any new skin lesions to your veterinarian. | | Vision changes or eye redness | Serious, especially in blastomycosis cases | Seek veterinary care promptly. Eye involvement in fungal disease needs urgent attention. | Liver monitoring is a routine part of longer courses. Your veterinarian will decide how often to check blood work based on your dog's dose, duration, and overall health. ## Who Should Not Take Itraconazole and What Interacts With It Itraconazole is not right for every dog. Tell your veterinarian about every medication, supplement, and topical product your dog uses before starting treatment. Dogs with pre-existing liver disease need careful evaluation. Itraconazole is processed by the liver, and dogs with compromised liver function may not clear it normally. Pregnancy and breeding status matter too. If your dog is pregnant, nursing, or intended for breeding, tell your veterinarian so they can weigh the risks and benefits. Drug interactions are a major concern with this medication. Itraconazole affects how the liver breaks down many other drugs, which can raise those drugs to unsafe levels. It can also interact with stomach acid reducers, which may lower itraconazole absorption. The interaction effect is real and measurable. In a study of healthy human subjects, itraconazole increased exposure to another drug by roughly 30 to 58 percent depending on the measurement, and prolonged its half-life [3]. That kind of interaction is exactly why your veterinarian needs a complete medication list. If your dog takes heart medication, seizure medication, antibiotics, or itch relief drugs, mention all of them. For a sense of how weight-based dosing works for other common dog medications, see our guides on [Apoquel oclacitinib daily dosing](/knowledge/veterinary-medicine/calculators-clinical-tools/apoquel-oclacitinib-daily-dose-itch-relief-dosing-chart-for-dogs), [pimobendan cardiac dosing](/knowledge/veterinary-medicine/calculators-clinical-tools/pimobendan-vetmedin-cardiac-dose-weight-based-chf-dog-dosing-chart), and [antibiotic dosage calculation for dogs](/knowledge/veterinary-medicine/clinical-pharmacology/antibiotic-dosage-calculation-dogs-practical-guide). The same principle applies across all of them. The dose is calculated for your individual dog, not copied from a chart. ## Overdose: What to Do and Who to Call If your dog ate more itraconazole than prescribed, act right away. Signs of overdose can include severe vomiting, drooling, wobbliness, and lethargy. In serious cases, liver injury can follow. Call your veterinarian or an emergency veterinary hospital immediately. If they are not available, contact a pet poison control service. Have the medication bottle with you so you can read the strength and the number of capsules or milliliters your dog may have taken. Do not wait for symptoms to appear before calling. With a drug that is processed by the liver, early decontamination and monitoring can make a real difference. ## Limitations and When to Contact a Veterinarian No article can tell you the right dose for your dog. Individual cases need a veterinarian who can examine your dog, review blood work, and adjust treatment over time. Use the information here to ask better questions, not to replace your veterinary team. Contact your veterinarian the same day if you notice: - Vomiting that does not stop or keeps coming back - Your dog refuses food for more than a day - Yellow tint to the gums, eyes, or skin - New weakness, wobbliness, or confusion - Any new skin sores or swelling Go to an emergency clinic now if your dog: - Collapses or has trouble breathing - Has a seizure - Shows severe lethargy and will not stand - May have eaten a large number of capsules Schedule a routine visit if: - Your dog seems to be improving but you are unsure whether to keep giving the medication - You are running low and need a refill before the next monitoring appointment - You notice mild appetite changes that come and go Keep every monitoring appointment. For systemic fungal infections, treatment often lasts many months. In one study, dogs with blastomycosis were treated for a median of 7.9 months [1]. Stopping early because your dog looks better can allow the infection to return, sometimes worse than before. ## Frequently Asked Questions ### How long does itraconazole treatment usually last for ringworm? Ringworm treatment typically runs for several weeks, and your veterinarian will confirm cure with repeat testing instead of appearance alone. Systemic fungal infections take much longer, often many months of daily treatment. Never stop early based on looks. ### Can I give itraconazole with food? Yes, giving it with food is the standard approach because it improves absorption. Pair the dose with a normal meal so your dog's drug levels stay steady. If your dog will not eat, call your veterinarian before skipping doses. ### Does my dog need blood tests during treatment? For deep fungal infections, yes, monitoring is expected. Veterinarians check drug levels and liver values, and most dogs need at least one dose adjustment along the way [1]. For short ringworm courses, your veterinarian will decide whether blood work is needed. ### What if my dog vomits right after the dose? Do not give another dose on your own. Call your veterinarian for instructions, since repeating a dose can lead to too much drug in the bloodstream. If vomiting happens often, your veterinarian may change the dose, the timing, or the formulation. ### Is itraconazole the same as other antifungals for dogs? No. Itraconazole is one specific triazole antifungal with its own dosing, monitoring, and interaction profile. Other antifungals used in dogs, including newer triazoles, have different pharmacokinetics and safety data [4]. Do not substitute one for another without veterinary direction. ## Related Articles - [Apoquel Oclacitinib Daily Dose: Itch Relief Dosing Chart for Dogs](/knowledge/veterinary-medicine/calculators-clinical-tools/apoquel-oclacitinib-daily-dose-itch-relief-dosing-chart-for-dogs) - [Pimobendan Vetmedin Cardiac Dose: Weight-Based CHF Dog Dosing Chart](/knowledge/veterinary-medicine/calculators-clinical-tools/pimobendan-vetmedin-cardiac-dose-weight-based-chf-dog-dosing-chart) - [Antibiotic Dosage Calculation for Dogs: A Practical Guide](/knowledge/veterinary-medicine/clinical-pharmacology/antibiotic-dosage-calculation-dogs-practical-guide) - [Amoxicillin Dog Cat Dose: Broad-Spectrum Antibiotic Weight-Based Guide](/knowledge/veterinary-medicine/calculators-clinical-tools/amoxicillin-dog-cat-dose-broad-spectrum-antibiotic-weight-based-guide) - [Cephalexin Weight-Based Antibiotic Dose Calculator: Veterinary Dosage Guide](/knowledge/veterinary-medicine/calculators-clinical-tools/cephalexin-weight-based-antibiotic-dose-calculator-veterinary-dosage-guide) - [Veterinary Emergency Drug Dosing: Weight-Based Calculations](/knowledge/veterinary-medicine/emergency-critical-care/veterinary-emergency-drug-dosing-weight-based-calculations) - [Itraconazole Side Effects in Dogs: What to Watch](/knowledge/veterinary-medicine/pet-medication-guide/itraconazole-side-effects-dogs) - [Ketoconazole for Dogs: Dosage, Uses, and Side Effects](/knowledge/veterinary-medicine/pet-medication-guide/ketoconazole-for-dogs-dosage-uses) - [Praziquantel for Dogs: Dosage and How Long It Takes](/knowledge/veterinary-medicine/pet-medication-guide/praziquantel-dogs-dosage-how-long) ## References 1. [Therapeutic drug monitoring of itraconazole in treatment of blastomycosis in dogs](https://pubmed.ncbi.nlm.nih.gov/41742595/). Journal of veterinary internal medicine, 2026. 2. [Bioassay and liquid chromatography-mass spectrometry are not equivalent in itraconazole therapeutic drug monitoring in dogs](https://pubmed.ncbi.nlm.nih.gov/42710535/). American journal of veterinary research, 2026. 3. [Effect of itraconazole on pharmacokinetics of ZX-7101A tablets in healthy Chinese subjects](https://pubmed.ncbi.nlm.nih.gov/41487500/). Frontiers in pharmacology, 2025. 4. [Single-Dose, Intravenous, and Oral Pharmacokinetics of Isavuconazole in Dogs](https://pubmed.ncbi.nlm.nih.gov/40200720/). Journal of veterinary pharmacology and therapeutics, 2025. ## Further Reading - [American Veterinary Medical Association: First Aid Tips for Pet Owners](https://www.avma.org/resources-tools/pet-owners/emergencycare/first-aid-tips-pet-owners) - [Merck Veterinary Manual: Dog Owners](https://www.merckvetmanual.com/dog-owners) - [Cornell Richard P. Riney Canine Health Center: Canine Health Information](https://www.vet.cornell.edu/departments-centers-and-institutes/riney-canine-health-center/canine-health-information)